PorKen

Does this engine have those anti-mushroom-sleeve thingamajobs fitted?

pmotts

I am pretty sure I saw some pornographic pictures of this motor being built some time ago and they had decked it or whatever you call it.

hacker-pschorr

It's probably the same motor, I'm not 100% sure. I'll find out when I talk to him tonight.

pmotts

I think you may have been the one who shared them, HP, I mean Enzo.
Closed deck, that's the term I was looking for.
Jim

hacker-pschorr

You are thinking of the engine with the steel sylinders pressed into the 928 block (with the original cylinders cut out). Porken is talking about a thin steel ring that is placed around the outside of the cylinder to keep it from expanding.

I'm not sure if this block has those rings installed.

The steel cylinder motors are larger displacement.

This is what the rings look like Porken brought up (not sure if they are on this motor):
http://members.rennlist.com/pageauto/block.htm

This is the steel cylinder motor you are talking about:
https://rennlist.com/forums/928-forum/239222-110mm-bore-928-engine-project-plans-for-a-7-4-liter-in-the-works.html

Vilhuer

S4 crank + stock lenght 150mm 928/944/951 rods + 951 pistons = about 2mm below deck level on TDC.

Just today I was picking GTS heads from machine shop and machinist mentioned its better to have piston come little above deck than just deck level. According to his tests in Ford 5.0L engines this alone can mean 20 hp more. So having same engine size, compression ratio, basic head design, valves, cams etc. but higher TDC piston position means more hp.

Z

The Murf "wife's car" has been to the 15psi neighborhood on pump gas with the completely stock engine. There's at least one stock engined GT going to 13psi on pump gas too.

Tim's dyno was 556 SAE, but that was well over three years ago already. I can guarantee you that number isn't of much value anymore.

He didn't really do any ignition timing tuning because they ran out of time. Basically timing was set for safety and they concentrated on fuel. Even that was probably more for testing and evaluating the logging and tuning equipment. The air/fuel is still richer than what should give maximum power. There's definitely more left in this setup, but this is basically for educational and equipment functionality verification purposes at this point.

Not really. The 22psi would be an additional atmosphere and a half above normal atmospheric pressure. If a stock S4 A/T makes around 250hp at the wheels, then an additional 1.5 atmospheres would theoretically bring that up to 625hp. This was done on a Dynocom dyno, and not a DynoJet. As has already been mentioned, the DynoJets give higher numbers, so that's part of it, but the numbers are probably about where they should be. There'd be more with additional tuning, and don't forget that there are higher drivetrain losses with the A/T than with a 5-speed car, so the rwhp numbers would be less than a 5-speed at the same boost level.

Stock rods, and the pistons don't go up to the deck, as you mentioned. I've been telling him he needs to get different pistons or rods in there to change that, but this is really just kind of a low budget test type engine to try some things out. If you do end up breaking something while making sure things work, it's better to break relatively cheap and easily available stuff.

The 100% stock A/T has never had a problem the whole time he's had the car. That's even with him having drag radials on there.

The DynoJets do read higher. The manufacturer of this dyno and also the manufacturer of the SuperFlow dynos both say that multiplying their SAE numbers by by 1.1 gives the equavalent DynoJet numbers, but I have no idea of how accurate that really is at this point. Using that 1.1 factor would make these Dynocom numbers equavalent to 639rwhp on a DynoJet, and I believe those would then be DynoJet SAE numbers. Maybe one of these days with more tuning, tweaking, and maybe a little more boost, I can talk him into going to a DynoJet, using DynoJet STD numbers, and going for 700. With enough arm twisting, maybe there'd even be more than one 700rwhp 928 there then.

IcemanG17

Great #'s.......is this his custom sleeved closed deck motor....???

hacker-pschorr

No, see post #22

Z

As far as I know-

This engine:
5.0 liter, stock crank, stock rods, 951 pistons, stock heads, Porsche cams, stock intake, stock exhaust manifolds. Horsepower so far as shown above.

The other engine that some have asked about:
7 liters, custom stroker crank, custom rods, custom pistons, custom wet sleeve hardened steel cylinders, ported, polished and flow bench tested big valve heads, custom cams, modified intake, big tube headers, probably more. Horsepower expected to be more than shown above.

mark kibort

wow, confusing

so, with a normal stroker, ive heard 968 pistons, stock 928 rods and then the devek or scat crank with the 928 journals. are those 968 pistons different with the offset than 951s? they must be right. 951 pistons more like 928 4.7 or 5 liter pistons?

thanks,

Mk

BC

I can't wait until I get my stuff together.

Can you PM me his number again hacker? Remember, I mentioned I switched phones and lost his and your number. Tim's Too. Thanks.

IcemanG17

Okay.....i guess reading the previous posts HELPS......duh

I thought this was the jewelry looking sleeve motor.....

Those mini sleeves sure look interesting...to squeeze the top of the cylinder..vs a complete liner....

So heres another ????

Why didn't he "O" ring the motor like the booster 951's.....that seems to help in high boost scenarios??

hacker-pschorr

Um yea,,,,,,we all talked about that and it was decided it would be best if you kept them lost....


He's running a Cometic triple layer metal gasket (I can sense the huge smile on Brendan's face as he reads this)

AO

OUCH!